Lynn Margulis (born Lynn Petra Alexander; March 5, 1938 – November 22, 2011) was an American evolutionary biologist, who was the primary modern proponent for the significance of symbiosis in evolution. In particular, Margulis transformed and fundamentally framed biologists' understanding of the evolution of the Eukaryotes, organisms with nuclei in their cells.

She proposed that they came into being by symbiotic mergers of bacteria. Margulis was the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a unified self-regulating system, and the principal defender and promulgator of the five kingdom classification of Robert Whittaker.

Throughout her career, Margulis' work could arouse intense objections, and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals. Her position sparked lifelong debate with leading neo-Darwinian biologists, including Richard Dawkins, George C. Williams, and John Maynard Smith.

Early life and education

Lynn Petra Alexander was born on March 5, 1938 in Chicago, to a Jewish family. Her parents were Morris Alexander and Leona Wise Alexander. She was the eldest of four daughters. Her father was an attorney who also ran a company that made road paints. Her mother operated a travel agency. She entered Hyde Park High School in 1952, describing herself as a bad student who frequently had to stand in the corner. at the age of fifteen. In 1957, at age 19, she earned a BA from the University of Chicago in Liberal Arts. She joined the University of Wisconsin to study biology under Hans Ris and Walter Plaut, graduating in 1960 with an MS in genetics and zoology. (Her first publication, published with Plaut in 1958 in the Journal of Protozoology, was on the genetics of Euglena, which are flagellates that have features of both animals and plants.) She then pursued research at the University of California, Berkeley, under the zoologist Max Alfert. Before she could complete her dissertation, she was offered research associateship and then lectureship at Brandeis University in Massachusetts in 1964. It was while working there that she obtained her PhD from the University of California, Berkeley in 1965. Her thesis was An Unusual Pattern of Thymidine Incorporation in Euglena.

Career

In 1966 she moved to Boston University, where she taught biology for twenty-two years. She was initially an Adjunct Assistant Professor, then was appointed to Assistant Professor in 1967. She was promoted to Associate Professor in 1971, to full Professor in 1977, and to University Professor in 1986. In 1988 she was appointed Distinguished Professor of Botany at the University of Massachusetts at Amherst. She was Distinguished Professor of Biology in 1993. In 1997 she transferred to the Department of Geosciences at UMass Amherst to become Distinguished Professor of Geosciences "with great delight", the post which she held until her death.

Endosymbiosis theory

thumb|The [[chloroplasts of glaucophytes like this Glaucocystis have a peptidoglycan layer, evidence of their endosymbiotic origin from cyanobacteria.]]

In 1966, as a young faculty member at Boston University, Margulis wrote a theoretical paper titled "On the Origin of Mitosing Cells". The paper, however, was "rejected by about fifteen scientific journals," she recalled. It was finally accepted by Journal of Theoretical Biology and is considered today a landmark in modern endosymbiotic theory. Weathering constant criticism of her ideas for decades, Margulis was famous for her tenacity in pushing her theory forward, despite the opposition she faced at the time. This formed the first experimental evidence for the symbiogenesis theory.

In 1995, English evolutionary biologist Richard Dawkins had this to say about Lynn Margulis and her work:

<blockquote>I greatly admire Lynn Margulis's sheer courage and stamina in sticking by the endosymbiosis theory, and carrying it through from being an unorthodoxy to an orthodoxy. I'm referring to the theory that the eukaryotic cell is a symbiotic union of primitive prokaryotic cells. This is one of the great achievements of twentieth-century evolutionary biology, and I greatly admire her for it.

She later formulated a theory that proposed symbiotic relationships between organisms of different phyla, or kingdoms, as the driving force of evolution, and explained genetic variation as occurring mainly through transfer of nuclear information between bacterial cells or viruses and eukaryotic cells.

Like other early presentations of Lovelock's idea, the Lovelock-Margulis 1974 paper seemed to give living organisms complete agency in creating planetary self-regulation, whereas later, as the idea matured, this planetary-scale self-regulation was recognized as an emergent property of the Earth system, life and its physical environment taken together. When climatologist Stephen Schneider convened the 1989 American Geophysical Union Chapman Conference around the issue of Gaia, the idea of "strong Gaia" and "weak Gaia" was introduced by James Kirchner, after which Margulis was sometimes associated with the idea of "weak Gaia", incorrectly (her essay "Gaia is a Tough Bitch" dates from 1995 – and it stated her own distinction from Lovelock as she saw it, which was primarily that she did not like the metaphor of Earth as a single organism, because, she said, "No organism eats its own waste").

Five kingdoms of life

In 1969, life on earth was classified into five kingdoms, as introduced by Robert Whittaker. Margulis became an early supporter as well as critic. While supporting parts, she was the first to recognize the limitations of Whittaker's classification of microbes. But newly discovered organisms such as the archaea and the emergence of molecular taxonomy challenged the concept. By the mid 2000-aughts most scientists began to agree that there are more than five kingdoms. Contrarily, Margulis became the most important defender of the five-kingdom classification. She rejected the three-domain system introduced by Carl Woese in 1990, which gained wide acceptance. She introduced a modified classification by which all life forms, including those newly discovered, could be accounted for in the 'classical' five kingdoms.

According to Margulis, the main problem lay with the treatment of archaea, which in her view should be grouped with bacteria under the kingdom Prokaryotae. This contrasts with both the three-domain system—which treats archaea as a domain (and a higher taxon than kingdom)—and with the six-kingdom system, (which holds that archaea is a separate kingdom). It has been suggested that it is mainly because of Margulis that the five-kingdom concept survives. Williamson's paper provoked immediate response from the scientific community, including a countering paper in PNAS.

AIDS/HIV theory

In 2009 Margulis and seven others authored a position paper concerning research on the viability of round body forms of some spirochetes, "Syphilis, Lyme disease, & AIDS: Resurgence of 'the great imitator'?" which states that, "Detailed research that correlates life histories of symbiotic spirochetes to changes in the immune system of associated vertebrates is sorely needed", and urging the "reinvestigation of the natural history of mammalian, tick-borne, and venereal transmission of spirochetes in relation to impairment of the human immune system". The paper went on to suggest "that the possible direct causal involvement of spirochetes and their round bodies to symptoms of immune deficiency be carefully and vigorously investigated". Seth Kalichman, a social psychologist who studies behavioral and social aspects of AIDS, cited her [Margulis] 2009 paper as an example of AIDS denialism "flourishing", and asserted that her [Margulis] "endorsement of HIV/AIDS denialism defies understanding".

Reception

Historian Jan Sapp has said that "Lynn Margulis's name is as synonymous with symbiosis as Charles Darwin's is with evolution." a "vindicated heretic", or a scientific "rebel", It has been suggested that initial rejection of Margulis' work on the endosymbiotic theory, and the controversial nature of it as well as Gaia theory, made her identify throughout her career with scientific mavericks, outsiders, and unaccepted theories generally. and in the commemorative collection of essays Lynn Margulis: The Life and Legacy of a Scientific Rebel, commentators again and again depict her as a modern embodiment of the "scientific rebel",

Awards and recognitions

  • 1975, Elected Fellow of the American Association for the Advancement of Science.
  • 1985, Guest Hagey Lecturer, University of Waterloo.
  • 1986, Miescher-Ishida Prize.
  • 1997, elected to the Russian Academy of Natural Sciences.
  • 1998, recipient of the Distinguished Service Award of the American Institute of Biological Sciences.
  • 1999, recipient of the William Procter Prize for Scientific Achievement.
  • 1999, recipient of the National Medal of Science, awarded by President William J. Clinton.
  • 2001, Golden Plate Award of the American Academy of Achievement
  • 2002–05, Alexander von Humboldt Prize.
  • 2005, elected President of Sigma Xi, The Scientific Research Society.
  • 2008, one of thirteen recipients in 2008 of the Darwin-Wallace Medal, heretofore bestowed every 50 years, by the Linnean Society of London.
  • 2010, inductee into the Leonardo da Vinci Society of Thinking at the University of Advancing Technology in Tempe, Arizona.
  • 2010, NASA Public Service Award for Astrobiology.
  • 2017, the Journal of Theoretical Biology 434, 1–114 commemorated the 50th anniversary of "The origin of mitosing cells" with a special issue
  • Honorary doctorate from 15 universities. They divorced in 1980.

She commented, "I quit my job as a wife twice," and, "it's not humanly possible to be a good wife, a good mother, and a first-class scientist. No one can do it — something has to go." As her wish, she was cremated and her ashes were scattered in her favorite research areas, near her home.

Works

Books

  • Margulis, Lynn (1970). Origin of Eukaryotic Cells, Yale University Press,
  • Margulis, Lynn (1982). Early Life, Science Books International,
  • Margulis, Lynn, and Dorion Sagan (1986). Origins of Sex: Three Billion Years of Genetic Recombination, Yale University Press,
  • Margulis, Lynn, and Dorion Sagan (1987). Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, HarperCollins,
  • Margulis, Lynn, and Dorion Sagan (1991). Mystery Dance: On the Evolution of Human Sexuality, Summit Books,
  • Margulis, Lynn, ed. (1991). Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, The MIT Press,
  • Margulis, Lynn (1992). Symbiosis in Cell Evolution: Microbial Communities in the Archean and Proterozoic Eons, W.H. Freeman,
  • Sagan, Dorion, and Margulis, Lynn (1993). The Garden of Microbial Delights: A Practical Guide to the Subvisible World, Kendall/Hunt,
  • Margulis, Lynn, Dorion Sagan and Niles Eldredge (1995) What Is Life?, Simon and Schuster,
  • Margulis, Lynn, and Dorion Sagan (1997). Slanted Truths: Essays on Gaia, Symbiosis, and Evolution, Copernicus Books,
  • Margulis, Lynn, and Dorion Sagan (1997). What Is Sex?, Simon and Schuster,
  • Margulis, Lynn, and Karlene V. Schwartz (1997). Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, W.H. Freeman & Company,
  • Margulis, Lynn (1998). Symbiotic Planet: A New Look at Evolution, Basic Books,
  • Margulis, Lynn, et al. (2002). The Ice Chronicles: The Quest to Understand Global Climate Change, University of New Hampshire,
  • Margulis, Lynn, and Dorion Sagan (2002). Acquiring Genomes: A Theory of the Origins of Species, Perseus Books Group,
  • Margulis, Lynn (2007). Luminous Fish: Tales of Science and Love, Sciencewriters Books,
  • Margulis, Lynn, and Eduardo Punset, eds. (2007). Mind, Life and Universe: Conversations with Great Scientists of Our Time, Sciencewriters Books,
  • Margulis, Lynn, and Dorion Sagan (2007). Dazzle Gradually: Reflections on the Nature of Nature, Sciencewriters Books,

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Chapters

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Journals

Explanatory notes

References